Following the Civil War, women in New York City began to clamor for advanced education at Columbia University. Although the professors of the classics felt that women in the classroom were a distraction, women were welcomed into geology, physics, and chemistry classes (Rosenberg, 2004). For almost thirty years, women learned, side by side with men, in geology classes until the School of Engineering—then one of the largest schools at Columbia University—determined that it was improper for women and men to conduct fieldwork together. The School enacted a ban on women in the later 1890s, a ban enforced until the height of the Second World War. Despite this deterrent, women continued to study geology at both Columbia College and Barnard College. The first woman to receive her Ph.D. in geology from Columbia University was Lea McIlvaine Luquer, who submitted a thesis in 1894 entitled, “The optical recognition and economic importance of the common mineral found in building stones: The relative effects of frost and the sulphate soda tests on building stones.” In 1929, Katharine Fowler was the first woman to receive her Ph.D. from Columbia University based on major geological fieldwork studying anorthosites in Laramie, Wyoming. She conducted two summers of fieldwork with only a pistol and a dog as her field assistants (Figure 1); no man would accompany her to the field. Fowler later went on to map Sierra Leone and to teach at Wellesley College.